A principle concern of electronic circuit designers is controlling the heat that is generated during operation of the circuit. Control of heat is vital to prevent component or circuit failure caused by heat buildup. The generally preferred method to control circuit and component heat is to dissipate it into the atmosphere around the circuit before temperatures rise to a damaging level. To do this, designers usually associate heat transfer devices, such as heat sinks, with heat generating components in the circuit. Heat sinks are designed to absorb the heat from the components and radiate the heat into the surrounding atmosphere.
Heat transfer devices are generally composed of a material with favorable heat transfer, or thermal conductive, characteristics; that is, the material should be able to absorb heat and radiate heat into the surrounding atmosphere in an efficient manner. Several metals have favorable thermal conductive characteristics, including copper, aluminum, steel, and their alloys. Any one of these materials can be used as a heat sink, but aluminum is generally the preferred material because copper is expensive and steel is not very malleable. Another reason aluminum is favored is that extrusion processes are preferred in the manufacture of heat transfer devices, and such processes favor aluminum.
Commercially available heat transfer devices come in a variety of shapes and sizes. Designers have developed a number of methods to combine these commercially available devices with heat generating circuits and components. These methods have generally been satisfactory, except in the case of low profile electronic systems. It has been found that very few of the commercially available heat transfer devices are suitable for controlling the heat generated by a large number of components in a very limited space.
Most commercially available heat transfer devices can control the heat of only one or two electronic components. This means that several heat transfer devices may be required for a single circuit. This may be acceptable for larger electronic systems, but is a distinct disadvantage where the electronic system is a compact or low profile system for which space is limited.
In many cases, heat spreaders can be mounted on the circuit substrate with heat generating components mounted on the spreaders. In the case of compact systems, such spreaders frequently have to be specially designed, which increases the cost of the system and may create ancillary storage and handling problems during manufacture. These spreaders are frequently combined with custom heat transfer devices in the design of heat control systems.
When custom heat transfer devices are used, the devices and their associated electronic components are typically assembled with clamps, nuts and screws, any one of which fastening methods involves a large number of small difficult to handle parts. This type of conventional assembly process requires several small parts to be meticulously handled with the aid of customized jigs, fixtures and other hand tools. This type of handling generally complicates the manufacturing process and makes it slower, more costly and inherently less reliable. Additionally, it can be anticipated that a number of completed circuits will be rejected for quality control reasons because leads become bent or misaligned due to vibration and handling.
Accordingly, what is needed in the art is a heat transfer device that can be associated with a circuit and the heat generating components on the circuit using a simple attachment method requiring the use of substantially fewer parts in the assembly process than prior art methods. The device should advantageously handle a number of heat generating components and should lend itself to being used in the manufacture of low profile systems. Such a device would be most advantageously employed if it could also function as a component in combination with other devices in a heat control system as well as a stand alone heat control device.